This customer wanted an input for an instrument with a low-level line output. He needed a preamp with a gain of 10X to bring this output up to Aries signal levels. I made him a new front panel for his AR-323 Mixer and squeezed together the three columns of jacks to add a 4th column. I added a 1/4" low level input with a gain control, output jack, and a switch to mix this output into the A channel, B channel, or neither. He asked for the text across the bottom.

Because I was unsure of exactly 10X gain, I designed the preamp with a trimmer for a variable gain of 5X to 15X. The circuit fits on a small daughter PCB that is added above the unused PCB space.

I made an aluminum bracket mounted by the three potentiometers to mount the PCB with ample space to protect the small extension. I left the stock wiring length and simply replaced the potentiometers and jacks. I even moved the two labels.

I did the first module conversion and sent the customer a second bracket and he did the second module conversion. Here are his two AR-106s in the lower cabinet on the left. They blend in very nicely.

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